US 7018382 B2
The bone marrow mixing instrument having a handle housing with a trigger mounted thereto. The handle housing contains a ratchet drive feed mechanism with a pawl assembly and a moveable ratchet bar. The other end of the ratchet bar is secured to a mixing housing which holds syringes filled with material and defines channels leading from the syringe area to a mixing nozzle removably mounted to the mixing housing. A piston rod and piston are mounted in each syringe containing bone defect material with a piston being advanced within the respective syringe by the feed mechanism to discharge bone defect material from the syringe into the adjacent channels in the mixing housing and into the mixing nozzle.
1. A bone marrow mixing instrument comprising: a handle assembly, a mixing housing connected to said handle assembly, a drive mechanism moveably mounted in said handle assembly and secured to said mixing housing, said mixing housing defining chambers to hold syringe tubes of different diameters and material pathways leading from said chambers to a nozzle section of said mixing housing, piston means including a piston rod and a piston head mounted to said piston rod, said piston rod and piston head being slidably mounted in each of said syringe tubes, trigger means pivotally mounted to said handle housing, said trigger means when pulled causing said drive mechanism to sequentially transport said mixing assembly toward said handle assembly, and a locking means mounted in said handle assembly to lock said piston rods in a fixed position.
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16. A bone marrow mixing instrument comprising: a handle housing and a trigger mechanism rotatably mounted to said handle housing, said trigger mechanism being biased outward by spring means mounted in said handle housing and engaging said trigger mechanism, a rachet drive mounted in said housing, said ratchet drive including a moveable ratchet bar mounted in said handle housing with the a distal end of said ratchet bar being secured to a mixing housing, said mixing housing defining chambers for receiving syringe tubes and channels communicating with said syringe tube chambers leading to a distal end of said mixing housing, a cartridge dispenser mounted in said syringe chamber, said cartridge dispenser comprising a syringe tube handle, a piston head mounted in said syringe tube and a piston rod mounted to said piston head, a drive mechanism mounted in said handle assembly causing said ratchet bar to be sequentially driven by the action of said trigger mechanism rearward through said handle housing causing each said piston head to move in said syringe barrel to dispense material held in said syringe barrel along said mixing housing channels into and through a nozzle mounted to said mixing housing, said nozzle defining a central throughgoing bore with a helix mixing member mounted therein.
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24. A bone marrow mixing instrument comprising: a handle housing and a trigger member moveably mounted to said handle housing, said trigger member being biased outward from said handle housing by spring means mounted in said handle housing and engaging said trigger member, a rachet drive mounted in said handle housing, said rachet drive including a toothed rachet member moveably mounted in said handle housing with a pawl member mounted on said trigger member engaging said ratchet bar causing said ratchet bar to be sequentially driven when said trigger member is pulled toward said handle housing rearward through said handle housing, a distal end of said ratchet bar being secured to a mixing housing, said mixing housing defining a ratchet bar receiving chamber, a plurality of chambers for receiving syringe barrels of different diameters and conduit pathways communicating with said syringe barrel chambers and leading a discharge conduit located at a distal end of said mixing housing, a cartridge material dispenser mounted in each of said syringe chambers, said cartridge material dispenser comprising a syringe barrel, a piston head mounted in said syringe barrel and a piston rod mounted to said piston head, said ratchet bar when sequentially driven by the action of said trigger member and associated pawl member rearward toward said handle housing transporting said mixing housing causing each piston head mounted in said syringe barrel to move in said syringe barrel toward a tip of said syringe barrel to dispense material held in each of said syringe barrels through said mixing housing channels into and through a nozzle mounted to said mixing housing.
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38. A bone defect material mixing instrument comprising: a handle housing, a trigger member pivotally mounted to said handle housing, said trigger member being biased outward from said handle housing by spring means mounted in said handle housing and engaging said trigger member, a ratchet bar moveably mounted in said handle housing, a ratchet drive having a pawl member mounted on said trigger member engaging said ratchet bar causing said ratchet bar to be sequentially driven by the action of said trigger member rearward through said handle housing when said trigger member is pulled against said handle housing, a distal end of said ratchet bar being secured to a mixing housing, said mixing housing defining a ratchet bar receiving chamber, a plurality of chambers for receiving syringe tubes of different diameters and conduit pathways communicating with said syringe tube chambers and leading to a distal end of said mixing housing, a cartridge material dispenser mounted in said syringe chamber, said cartridge material dispenser comprising a syringe barrel, sterile flowable material for application to a bone defect area contained within said barrel, a piston head mounted in said syringe barrel and a piston rod mounted to said piston head, said pawl member engaging said ratchet bar and causing said ratchet bar to be sequentially driven by the action of said trigger member rearward toward said handle housing carrying said mixing housing and causing each said piston head mounted in said syringe barrel to move in said syringe barrel toward a tip of said syringe barrel to dispense material held in said syringe barrel along said channels into and through a nozzle mounted to said mixing housing, said nozzle defining a central throughgoing bore with a helix mixing member mounted therein.
There are no related applications.
The present invention generally relates to a bone marrow mixing instrument for the repair and replacement of the various portions of the human skeletal system. The present invention is specifically directed to provide a bone marrow mixing instrument having two cartridges, one containing bone marrow and one containing a scaffolding material such as demineralized bone material mounted on a pistol type handle with a trigger activated feeding mechanism. The bone marrow and scaffolding material composition is driven by a dual plunger/piston assembly into a mixing housing and exits the mixing housing via a nozzle on to the bone defect site.
Bone grafting is widely used to treat fractures and bone defect areas. Autogenous cancerous bone, which is taken from one site in the graftee and implanted in another site in the graftee, is currently the most effective bone graft and provides the scaffolding to support the distribution of the bone healing response and also provides the connective tissue progenitor cells which form new cartilage or bone. However, the harvest of autogenous bone results in significant cost and morbidity, including scars, blood loss, pain, prolonged operative and rehabilitation time and risk of infection. Furthermore, in some clinical settings, the volume of material necessary at the graft site can exceed the volume which can be extracted from the available autograft. Accordingly, alternatives to autografts have been developed in an attempt to reduce the problem of morbidity and cost of bone grafting procedures.
Several purified or synthetic materials, including ceramics, biopolymers, processed allograft bone and collagen-based matrices have been investigated or developed to serve as substitutes for autografts. The FDA has approved a porous coral derived synthetic hydroxyapatite ceramic for use in contained bone defects. A purified collagen/ceramic composite material is also approved for use in acute long bone fractures. Although these materials avoid the morbidity involved in harvesting autografts from the graftee and eliminate problems associated with a limited amount of available autograft, the clinical effectiveness of the synthetic materials generally is less than autografts.
Synthetic graft materials have also been used as carriers for bone marrow cells. When such composite materials have been implanted into skeletal defects, the connective tissue progenitor cells differentiated into skeletal tissue. In some instances, composite implants were made by soaking the synthetic graft material in a cell suspension obtained from bone marrow. However, the connective tissue progenitor cells, which have the capacity to differentiate into cartilage, bone and other connective tissue such as fat, muscle, and fibrous tissue are present in the bone marrow in very minute amounts. The numbers of such cells present in 1 ml of bone marrow varies widely from subject to subject ranging from about 100 cells to 20,000 cells depending to large extent on the age of the donor. This represents a mean of about one in 20,000 to one in 40,000 of the nucleated cells in bone marrow.
Demineralized bone material from allogenic sources has been available for over fifty years and has been demonstrated to facilitate healing of bony defects created by trauma, disease or surgical intervention. Demineralized bone material (DBM) is provided as a dry powder and in various carriers to improve the convenience of handling and wound placement. DBM acts as an osteoconductive scaffold as well as having some osteoinductive properties (ability to induce surrounding patient cells to grow new bone) by virtue of bone morphogenetic proteins (BMP's) retained in the DBM after the demineralization process.
Surgeons have previously used autologous bone, bone marrow and patient blood to provide osteoprogenitor cells to facilitate healing of bony defects. These procedures are highly effective to propagate new bone growth and accelerate wound healing. The use of bone chips and bone marrow taken from the patient's hip (iliac crest) or vertebral intertransverse processes, while providing an effective supply of osteogenic material, creates significant patient morbidity.
As an alternative, bone marrow can be aspirated from the patient, usually from the iliac crest, vertebral body sternum or long bone condyle. This bone marrow aspirate (BMA) contains blood serum, red blood cells and some specific osteoprogenitor cells known as mesenchymal stem cells (MSC) or pluripotential cells. Orthopaedic surgeons have used bone marrow aspirate to facilitate wound healing in spinal fusion, fracture management or other skeletal defects. BMA alone is a slightly viscous, sticky liquid and is difficult to manage for delivery to an operative surgical location. Some workers have mixed BMA with demineralized bone matrix and gotten superior healing rates.
The traditional and current technique involves removing BMA through a bone perforation biopsy-type device and collecting the BMA in a sterile syringe. The BMA is then discharged from the syringe into a container in the operating room. The DBM is then added to the BMA and manually mixed. DBM is provided in a sterile, freeze-dried granular form and delivered from a container, usually a glass bottle.
This manual procedure makes it difficult to control the mix ratio. It may also compromise sterility, as the mixing is being done in the open in the operating room. Once mixed, the formulation may be held for a time ranging from a few minutes to up to an hour and risk drying out and becoming even more difficult to manipulate in the defect area. Finally, the delivery from the mixing container is usually done with a spatula, which results in waste, namely, material being left behind in the container and a loss of the precious bone and marrow cells. Vigorous mixing may also damage the cells in the marrow. The present invention thus overcomes these procedures which are difficult to implement: namely; time constraints, loss of sterility, preservation of cell viability and eliminate waste of material.
The prior art has attempted to solve the problems which occur in mixing bone marrow with a scaffolding material. Isolated marrow cells from quail, in solution, were implanted or delivered via soaking in blocks of calcium phosphate ceramics, the soaked blocks being deposited in subcutaneous sites in a nude mouse. The osteogenesis is a biphasic phenomena in which donor cells are largely responsible for osteogenesis in the first three to four weeks and in the second phase, eight to twelve weeks post surgery the host cells actions predominate and begin to show the formation of marrow of host origin. “The Origin of Bone Formed in Composite Grafts of Porous Calcium Phosphate Ceramic Loaded with Marrow Cells”, by J. Goshima et al., Clinical Orthopaedics and Related Research, vol. 269, pp. 275–283 (1991) Also of interest in this reference is the discussion of prior art on page 281, col. 1.
The use of a bone marrow cells in a bone graft is shown in several U.S. patents, namely, U.S. Pat. No. 5,824,084, issued Oct. 20, 1998 and U.S. Pat. No. 6,049,026 issued Apr. 11, 2000. These patents are directed toward a method for preparing a composite bone graft which includes providing a bone marrow aspirate suspension and passing the bone marrow aspirate suspension through a porous, biocompatible, implantable substrate, such as coralline hydroxyapatite, mineralized or demineralized cancerous bone sections, granules of demineralized bone, sintered cortical or cancerous bone and granular ceramics, to provide a composite bone graft having an enriched population of connective tissue progenitor cells. Because the method is preferably performed intraoperatively it reduces the number of occasions the graftee must undergo invasive procedures. The composite graft includes an enriched population of connective tissue progenitor cells and a greater number of connective tissue progenitor cells per unit volume than that found in the original bone marrow aspirate.
It is also known in the art to use a piston ram carried in a trigger activated gun type device to dispense material carried a cartridge which is loaded into the gun type device. A representative patent showing this type of dispenser is shown in U.S. Pat. No. 4,826,053 issued May 2, 1989.
The present invention is directed toward a pistol type bone marrow and demineralized bone mixing instrument utilizing a trigger which activates a rachet drive to advance plunger pistons in stacked syringe tubes containing demineralized bone material and bone marrow thus driving the same into a mixing head which discharge the mixed components at a predetermined ratio.
It is an object of the invention to provide a bone marrow mixing instrument having an ergonomically shaped pistol type handle to assist a physician in inserting mixed bone and bone marrow into a patient's defect site.
It is still another object of the invention to provide a bone marrow mixing instrument having a magazine which holds loaded syringe cartridges.
It is yet another object of the invention, to provide for the mixing of DBM or other scaffolding material with bone marrow of the patient being operated upon at a predetermined ratio conducive to bone healing.
It is a further object to provide a bone marrow instrument which mixes the bone marrow with a scaffolding material while precluding cell damage to the bone marrow cells.
It is still another object of the invention to provide a bone marrow mixing instrument having a locking member which holds the piston rods and piston heads in a fixed locked position inside syringe tubes used in the instrument.
It is yet another object of the invention to provide a bone marrow mixing instrument which allows different nozzles having different mixing characteristics to be selectively mounted to the bone mixing instrument.
These and other objects, advantages, and novel features of the present invention will become apparent when considered with the teachings contained in the detailed disclosure which along with the accompanying drawings constitute a part of this specification and illustrate embodiments of the invention which together with the description serve to explain the principles of the invention.
The preferred embodiment and best mode of the invention is shown in
The present invention is directed to a gun type bone marrow mixing instrument 20 for receiving bone marrow collected from a patient, mixing it with mineralized bone material, demineralized or partially demineralized bone material (DBM) such as DBX® manufactured by the Musculoskeletal Transplant Foundation, ceramics or other biocompatible materials in a predetermined precise ratio of marrow to DBM and delivering it directly to a bone defect site via a closed system. The DBM is in a pre-mixed form in a viscous excipient such as sodium hyaluronate or its derivation (HA). The HA is best formulated at physiological pH (6.5–7.5) and isotonic osmolality (250˜330 in Osmol/kg).
The delivery of bone marrow aspirate (BMA) into the surgical defect is difficult. The ratio of BMA to DBM is important. If there is too little BMA, the mixture is dry, grainy and has only a limited number of the osteogenic MSC's. Too much BMA and the mixture may be excessively sticky and of low viscosity, making it difficult to place the mixture in the operative site and problematical to retain it in position. Optimal ratios of BMA to DBM range from 1:1 to 6:1 (v/v) with a preferred ratio being 1:3.
The bone marrow mixing instrument 20 is constructed with a premolded handle assembly 30 having a rachet drive assembly 40 mounted therein which is advanced by a trigger mechanism 52 so that dual plunger or piston assemblies 60 and 70 as more clearly shown in
A toothed rachet bar 42 is mounted in handle slots 37. The rachet bar 42 is constructed of stainless steel 316 having an angled distal end 43 and a rounded proximal end 44 as shown in
The piston or plunger assemblies 60 and 70 have their respective piston rods 66,76 mounted in seats 36 and 38 formed in the handle. The piston rods 66, 76 of the piston assemblies each are formed with a central rod 67, 77 around which a plurality of spaced circular retainer members 68, 78 are placed. The spaced circular retainer members 68,78 which are preferably 0.062±0.002 inches in width extend outward from the respective central rod and are spaced the same distance from each other to receive a locking member 100 as described below. As shown in
The trigger mechanism 52 comprises a trigger body 54 which is mounted by a pin 55 to the handle assembly 30. The pin 55 extends through bores 55 a The trigger body 54 defines a spring cavity 57 which holds one end of a bracing spring 56, the other end being held in a handle so that the trigger body 54 is continuously biased away from the handle. The biasing spring 56 as shown in phantom in
The small syringe tube 62 preferably contains bone marrow previously collected by the surgeon from the patient while the larger syringe tube 72 contains a demineralized or partially demineralized bone material which has been previously placed in the syringe in a sealed sterile condition. Both syringe tubes 62 and 72 are mounted in chambers 84 and 86 respectively which are formed in the mixing housing as shown in
A locking member 100 as shown in
The mixing housing 88 defines a lower chamber 82 as seen in
The nozzle 200 which is removably mounted on the nozzle connector member 90 via the locking flange structure 94 formed on the nozzle connector 90. The nozzle is constructed with a base plate 202 which has two curved ends 204 and linear sides 206 allowing the same to be inserted in the nozzle connector 90 with the bore 208 of the tube of the nozzle being seated over the circular boss 93 of the connector member 90. The nozzle is rotated so that the base plate curved ends 204 are frictionally held within space 96. The nozzle tube has exterior fluting 210 to aid in rotating the nozzle to lock the same in the connector 90. Mounted within the bore of the tube 208 is a helix 212 which is curved at an angle around 30° which reduces the forces acting on the marrow cells as they are mixed and discharged from the nozzle. The nozzle diameter is highly polished and provided clearance for the delivered material. It is important to note that when delivering marrow to the wound site, that cells can be damaged by corners, edges and rough surfaces as well as by force. The present invention allows for a short path for the marrow to travel with no edges and sharp turns. The path surface can be polished or coated with Teflon®, silicone or other low friction material which will lower shear stresses on the cells.
In operation, the surgeon perforates the patient's bone (ilea, vertebra, sternum or long bone condyle). The bone marrow is withdrawn, i.e., aspirated from the bone into the syringe tube 62. This syringe 62 is provided empty and is coated with heparin. This syringe has a luer lock tip 63 which mates with the proximal end of a separate bone marrow aspirate device. The empty, heparin coated syringe is used to withdraw the bone marrow from the patient's bone. Three to five cubic centimeters of bone marrow aspirate (BMA) may be collected in the second syringe. When it is filled, it will be placed into a receiving chamber 84 in the mixing housing and be adjacent and parallel to the first syringe 72 which, in this example holds the premixed demineralized bone material (DBM) and hyaluronic acid (HA) scaffoling material. This mixture is a flowable paste or putty and is within the property range previously disclosed.
A piston or plunger assembly is then placed rearward of the two syringe tubes with the piston head inside the tube and the assembly is inserted into the applicator gun. This plunger is sized to a specific pre-set volume and matches the actual BMA volume chosen and collected.
The operator squeezes the trigger of the applicator device and the rachet drive propels the contents of both syringe tubes simultaneously into and through the mixing tip/nozzle. The bone marrow will intermix with the DBM/HA as they simultaneously pass through the mixing tip/nozzle. The combined materials are then placed in the wound site by the surgeon.
The plunger assemblies shown in
The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention should not be construed as limited to the particular embodiments which have been described above. Instead, the embodiments described here should be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the scope of the present inventions defined by the following claims.
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